perf(quic): move connection migration check from hot path to 5s timer

Author: st0o0

src/Servus.Akka/Transport/Quic/Client/QuicTransportStateMachine.cs

@@ -7,6 +7,8 @@ namespace Servus.Akka.Transport.Quic.Client;
 public sealed class QuicTransportStateMachine
 {
     private const string ConnectTimerKey = "connect-timeout";
+    private const string MigrationCheckTimerKey = "migration-check";
+    private static readonly TimeSpan MigrationCheckInterval = TimeSpan.FromSeconds(5);
 
     private readonly ITransportOperations _ops;
     private readonly IActorRef _connectionManager;
@@ -51,7 +53,6 @@ internal void Dispatch(IQuicTransportEvent evt)
             case InboundData e:
                 if (e.Gen == _connectionGen)
                 {
-                    CheckForConnectionMigration();
                     _ops.OnPushInbound(new MultiplexedData(e.Buffer, e.StreamId));
                 }
                 else
@@ -139,6 +140,13 @@ public void HandleDownstreamFinish()
 
     public void OnTimer(string? timerKey)
     {
+        if (timerKey == MigrationCheckTimerKey)
+        {
+            CheckForConnectionMigration();
+            _ops.OnScheduleTimer(MigrationCheckTimerKey, MigrationCheckInterval);
+            return;
+        }
+
         if (timerKey != ConnectTimerKey || _pendingConnect is null)
         {
             return;
@@ -153,6 +161,7 @@ public void OnTimer(string? timerKey)
     public void PostStop()
     {
         _ops.OnCancelTimer(ConnectTimerKey);
+        _ops.OnCancelTimer(MigrationCheckTimerKey);
         CleanupTransport();
     }
 
@@ -238,6 +247,7 @@ private void OnConnectionLeaseAcquired(QuicConnectionLease lease)
         _connectionLease = lease;
         _connectionHandle = lease.Handle;
         _lastLocalEndPoint = _connectionHandle.LocalEndPoint();
+        _ops.OnScheduleTimer(MigrationCheckTimerKey, MigrationCheckInterval);
 
         _pumpManager = new QuicPumpManager(_self);
         _pumpManager.StartAcceptLoop(_connectionHandle);

src/Servus.Akka/Transport/Quic/Listener/QuicServerConnectionStage.cs

@@ -74,7 +74,7 @@ private void OnReceive((IActorRef sender, object message) args)
             }
         }
 
-        protected override void OnTimer(object timerKey) { }
+        protected override void OnTimer(object timerKey) => _sm.OnTimer(timerKey as string);
 
         public override void PostStop() => _sm.PostStop();
 

src/Servus.Akka/Transport/Quic/Listener/QuicServerStateMachine.cs

@@ -5,6 +5,9 @@ namespace Servus.Akka.Transport.Quic.Listener;
 
 internal sealed class QuicServerStateMachine
 {
+    private const string MigrationCheckTimerKey = "migration-check";
+    private static readonly TimeSpan MigrationCheckInterval = TimeSpan.FromSeconds(5);
+
     private readonly ITransportOperations _ops;
     private readonly IActorRef _self;
     private readonly QuicConnectionHandle _connectionHandle;
@@ -33,6 +36,7 @@ public void Start()
     {
         _connectionGen++;
         _lastLocalEndPoint = _connectionHandle.LocalEndPoint();
+        _ops.OnScheduleTimer(MigrationCheckTimerKey, MigrationCheckInterval);
 
         _pumpManager = new QuicPumpManager(_self);
         _pumpManager.StartAcceptLoop(_connectionHandle);
@@ -47,7 +51,6 @@ internal void Dispatch(IQuicTransportEvent evt)
             case InboundData e:
                 if (e.Gen == _connectionGen)
                 {
-                    CheckForConnectionMigration();
                     _ops.OnPushInbound(new MultiplexedData(e.Buffer, e.StreamId));
                 }
                 else
@@ -117,8 +120,18 @@ public void HandleDownstreamFinish()
         Cleanup();
     }
 
+    public void OnTimer(string? timerKey)
+    {
+        if (timerKey == MigrationCheckTimerKey)
+        {
+            CheckForConnectionMigration();
+            _ops.OnScheduleTimer(MigrationCheckTimerKey, MigrationCheckInterval);
+        }
+    }
+
     public void PostStop()
     {
+        _ops.OnCancelTimer(MigrationCheckTimerKey);
         Cleanup();
     }